DISCLAIMER: The cases / examples on this blog have been anonymised to maintain confidentiality of patients. Cases have been acquired from various international hospitals and through other medical colleagues with the intention to teach through case examples.

Friday, 27 April 2007

An elderly patient was originally admitted several weeks ago with a fever and after investigations, a urinary tract infection was diagnosed. The urine grew a drug resistant Proteus mirabilis that was probably acquired at the nursing home where the patient normally resides.

It was not initially know what the organism was and so a broad spectrum antibiotic cover was used (cetriaxone).

Initially, the patient made good progress until one week ago when fever recurred. After work-up, it was established that the patient had acquired a hospital infection from Pseudomonas aeruginosa and Group B streptococcus, with infiltration being noted at the lingula of the left upper lobe. Quite rightly, antibiotics were changed and the patient was started on piperacillin and tobramycin to which the organisms were sensitive.

However, the patient continued to deteriorate with no change in the spiking fever and with raised white cells and CRP.

A senior doctor was asked to consult for the patient because despite good antibiotic cover for the identified organisms, the chest xray was worsening.

Before seeing the patient the senior doctor was shown a recent Xray and it revealed a well circumscribed lesion in the right upper zone, not typical of a pneumonia.

Most importantly, going to see the patient gave a potential diagnosis.

On entering behind the curtain there was a very strong smell of anaerobic organisms, a similar smell of most hospital laboratories !! Knowing that the patient was diabetic, the feet were initially examined for infected diabetic foot ulcers. However, although there was some pressure areas, there was no ulceration.

The feet were smelt closely, but no smell was emminating from them. The smell was followed upwards and it became extremely strong from the patients MOUTH !!!!

A torch was shon in the mouth and it revealed a green exudate on the top of the right gum area consistent with an anaerobic infection. This patient's mouth was also extremely dry because of mouth breathing only.

Listening to the chest, there were reduced breath sounds at the right upper zone and crackles at the right base and left mid zone consistent with some of the Xray findings.

At this point, the diagnosis pointing to being a Lung Abscessfrom anaerobic infection until proven otherwise with possible aspiration pneumonia at the right base as well, although the Xray does not show obvious right basal changes, and hence, this shows just how important good clinical examination is.

It was advised that the patient see an oral specialist to ascertain if there was any evidence of oral abscess and to detail the dentition.

Moroever, this patient underwent CT scanning and it revealed an unusual but well circumscribed pneumonia rather than an abscess.

However, with an obvious oral anaerobic infection plus evidence of oral aspiration in addition to markers of infection, being unresponsive to aerobic cover antibiotic therapy and a well circumscribed right upper lobe lesion, the differential diagnosis should always include an anaerobic abscess.

The patient responded well to piperacillin and clindamycin and the infection resolved rapidly.

However, the oral anaerobic infection still persisted despite antibiotic therapy and good mouth cleansing.

The patient later developed a further pneumonia and this time it was diagnosed as a severe fungal pneumonia which was refractory to therapy and this was an indicator of severely impaired immunity.

The commonest cause of lung abscess is from anaerobic organisms and often the patient has poor dentition and aspirates the bacterial during respiration to predispose to the infection.

Moreover, this patient was immunocompromised due to diabetes and in addition, the patient had already had two other infections in recent weeks. Most significantly, the patient had Parkinson's disease and Lewy Body Dementia and had previously aspirated and thus, he was always at significant risk for this problem.

Of course, in this case, the presence of Psuedomonas may have been the cause of the abscess but certainly coverage of anaerobic organisms was warranted here.

Remember to always look at the FEVER CHART and a good indication of an abscess is the classical Spiking Fever. Try and keep things simple, like trusting your sense of smell, and often the diagnosis makes itself known to the doctor.

Hence, all that was needed was a nose, a stethoscope, an Xray and of course, Sherlock Holmes.

Today's story is thus Sherlock Nose !!

Have a great Golden Week !!!!Having passed this case on to Professor Tierney he made a number of observations:

Firstly, only 60% of bacteroides produce the typical anaerobic smell and hence, the absence of such as smell does not exclude the diagnosis of an anaerobic infection.

Secondly, in the patient without teeth, the presence of a lung abscess is lung cancer until proven otherwise. Original quote was: A lung abscess without teeth is cancer of the lung until proven otherwise- Prof Tierney